Controlled thermal cycling has recently been used as a treatment process for various alloy metals. The general usage of the thermal cycling process has been limited to steel alloys which normally include two or more alloying metals, namely combinations of cobalt, nickel, molybdenum, titanium, aluminum, chromium, magnesium, tungsten and vanadium. It has been found that thermal cycling of alloy metals improves the resistance of these metals to normal wear and tear. This is especially useful in the power tool field.
Recently, thermal cycling has been used to treat electrical power transmission equipment such as wires, cables, electric motors, etc. Such treatments have also been discovered to have beneficial properties when applied copper electrodes and spark plugs. These items have exhibited improved conductivity when so treated.
Orthopedic implants treated with a thermal cycling process have also exhibited higher durability and greater strength. Thermal cycling of the implants is disclosed in U.S. Pat. No. 5,044,422, owned by the assignee of this invention.
Thermal cycling processes affect the wearability of metal by four known mechanisms: Conversion of austenite to martensite; precipitation hardening which increases Rockwell hardness; formation of fine carbide particles; and residual stress relief.